What is the working principle of a manual transmission breather valve?

[Wade]

According to the torque principle of leverage, the low-speed gear with the largest diameter and longest radius amplifies the engine torque to assist the vehicle in starting forward movement. Through the shift fork: When shifting gears, the input shaft changes, and through the transmission of the intermediate shaft, it is ultimately output to the differential via the output shaft. When the differential moves, the tires move as well. That is, by using the shift fork, the transmission ratio of the meshing gears is altered, thereby changing the driving torque. The speed of the gears is inversely proportional to the number of teeth—the more teeth a gear has, the slower its speed. By combining a series of large and small gears, different transmission ratios can be achieved. Transmission gear set: The transmission consists of various gears and shafts, with gears being the core component. All gears can collectively be referred to as the gear set. Typically, there are three shafts inside the transmission: the input shaft, the output shaft, and an intermediate shaft.